Question

Subtract-2a^2+b^2-ab+a from the sum of:
a^2-b^2+2ab, a^2+4b^2-6ab, b^2+6, a^2-4ab and -2a^2+b^2-ab+a.​

Answer 1

Answer:

=a^2-b^2+2ab+a^2+4b^2-6ab+b^2+6+a^2-4ab+(-2a^2+b^2-ab+a)

=a^2-b^2+2ab+a^2-4b^2-6ab+b^2+6+a^2-4ab-2a^2+b^2-ab+a

=a^2+a^2+a^2-2a^2-4b^2-b^2+b^2+b^2+2ab-6ab-4ab-ab+a+6

=3a^2-2a^2-5b^2+2b^2+2ab-11ab+a+6

=a^2-3b^2-9ab+a+6

now,

a^2-3b^2-9ab+a+6-(-2a^2+b^2-ab+a)

=a^2-3b^2-9ab+a+6+2a^2-b^2+ab-a

=3a^2-4b^2-8ab+6

ans.